What is the best way to debug USB communication on STM32?

[Hassey]

I am working on an STM32 project that uses USB communication and I am trying to improve the debugging process. Sometimes it is difficult to identify whether an issue is coming from the firmware, USB configuration, or the connected device.

What tools or debugging methods do you normally use for USB-related issues on STM32?

[waclawek.jan]

A protocol debugger, which allows you to see what’s on the line.

There are some mid-price dedicated debuggers, I’ve heard praise on the TotalPhase offering in the past, but I haven’t used any personally. High-speed analyzers are pricier than the Full/Low-speed ones, but for STM32 usually the latter suffices. Some oscilloscopes/logic analyzers come with USB protocol decoding either built in or as an option, and sometimes it’s priced pleasantly, although its control may be perhaps not that well thought out than with the dedicated tool - you have to check yourself what’s available.

Other than that, just the usual - on-chip debugging, staring at standards, code and manuals…

JW

[Andrew Neil]

In addition to what ​@waclawek.jan said:

• Instrument your code, so that you can see what’s going on
• For a Device, Learn to use whatever debugging/diagnostic facilities the Host offers

[Richard Li]

Windows event log may find some clue, but too more “noise”

[TDK]

Wireshark is a free and useful option.

[Karl Yamashita]

You haven’t indicated what the STM32 is connected to? Is it a Windows computer or connected to another device with no OS? 

If it’s a computer, you can use Wireshark on that computer, and during install i believe you have an option to install USBPcap designed to capture USB packets.

If the latter, then you can use Total Phase Beagle USB 12 that connects in between the 2 devices. You can monitor the UUSB packets on a laptop/desktop using their Control Center Software

[Gyessine]

Hello ​@Hassey 
USB analyzer is the best option to track enumeration process, check descriptors and data transfer, however if you don’t have the hardware, you can use wireshark with USBPCAP extensions,it’s free and pure software solution however it doesn’t provide as much details as USB analyzer and you can’t use it in case your STM32 is acting as host
If you want to verify USB registers, a debug session using STM32CubeIDE (using SFR) or whatever is your toolchain) is basic and simple method, however it’s not ideal because pausing debug session will cause to halt the communication. You can consider andrew recommendation for advanced debugging
BR
Gyessine

[Andrew Neil]

If you want to verify USB registers, a debug session using STM32CubeIDE (using SFR) or whatever 

​@Hassey The trouble with this, of course, is that halting the CPU to examine registers will break the comms.

This is where instrumenting your code comes in ...